Arm chair



FIG. 1 is a left front perspective view of an arm chair showing my new design;

FIG. 2 is a side elevational view thereof, the opposite side elevational view being a mirror image;

FIG. 3 is a front elevational thereof; and,

FIG. 4 is a right rear perspective view thereof. 

The ornamental design for an arm chair, as shown and described. 